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| United States Patent |
5,654,251
|
|
Abbott
, et al.
|
August 5, 1997
|
Isoparaffin-olefin alkylation
Abstract
A novel alkylation catalyst is described which is used in processes for
alkylating olefin hydrocarbons with isoparaffin hydrocarbons to produce
high octane alkylate products suitable for use as a blending component of
gasoline motor fuel. The novel catalyst comprises a mixture of a hydrogen
halide and a sulfone. The novel alkylation catalyst is utilized in a novel
process for alkylating olefin hydrocarbons with isoparaffin hydrocarbons.
| Inventors:
|
Abbott; Ronald G. (Kingwood, TX);
Williams; Ralph P. (Bartlesville, OK);
Johnson; Marvin M. (Bartlesville, OK);
Vanderveen; John W. (Bartlesville, OK)
|
| Assignee:
|
Phillips Petroleum Company (Bartlesville, OK)
|
| Appl. No.:
|
458542 |
| Filed:
|
June 2, 1995 |
| Current U.S. Class: |
502/216; 502/224; 585/724; 585/730 |
| Intern'l Class: |
B01J 027/02 |
| Field of Search: |
585/724,730
502/216,168,169,224
|
References Cited
U.S. Patent Documents
| 3795712 | Mar., 1974 | Torck et al. | 585/724.
|
| 3862258 | Jan., 1975 | Huang et al. | 260/683.
|
| 3951762 | Apr., 1976 | Voss et al. | 204/59.
|
| 4024203 | May., 1977 | Torck et al. | 585/724.
|
| 4058575 | Nov., 1977 | Cahn et al. | 260/666.
|
| 4069268 | Jan., 1978 | Siskin et al. | 260/666.
|
| 4094924 | Jun., 1978 | Siskin et al. | 260/683.
|
| 4120912 | Oct., 1978 | Hulme | 260/683.
|
| 4311866 | Jun., 1982 | Chapman | 585/719.
|
| 4383977 | May., 1983 | Hutson, Jr. et al. | 422/235.
|
| 5191150 | Mar., 1993 | Child et al. | 585/809.
|
| 5262652 | Nov., 1993 | Child et al. | 585/802.
|
| 5292982 | Mar., 1994 | Del Rossi et al. | 585/724.
|
Primary Examiner: Lewis; Michael
Assistant Examiner: Dunn, Jr.; Thomas G.
Attorney, Agent or Firm: Stewart; Charles W.
Parent Case Text
This is a division of application Ser. No. 08/155,266, filed Nov. 22, 1993,
which is a division of application Ser. No. 08/075,427, filed Jun. 14,
1993, which is a continuation-in-part of application Ser. No. 07/877,338,
filed May 1, 1992, now abandoned.
Claims
That which is claimed is:
1. A method for decreasing the rate of vaporization of hydrogen fluoride
from a catalyst mixture containing hydrogen fluoride when said catalyst
mixture is released into the atmosphere from a process system, said method
comprising admixing a vapor pressure depressant amount of a sulfone to
said catalyst mixture to thereby form an admixture wherein said vapor
pressure depressant amount of said sulfone is such that the weight ratio
of hydrogen fluoride to sulfone in said admixture is at least 1:1 and the
amount of sulfone in said admixture is in the range of from about 2.5
weight percent to 50 weight percent; and
releasing said admixture into the atmosphere from said process system.
2. A method as recited in claim 1 wherein said vapor pressure depressant
amount of said sulfone in said admixture is in the range of from about 5
weight percent to about 30 weight percent.
3. A method as recited in claim 2 wherein said vapor pressure depressant
amount of said sulfone in said admixture is in the range of from about 10
weight percent to about 25 weight percent.
4. A method as recited in claim 1 wherein said sulfone is sulfolane.
5. A method as recited in claim 2 wherein said sulfone is sulfolane.
6. A method as recited in claim 3 wherein said sulfone is sulfolane.
7. A method for decreasing the rate of vaporization of hydrogen fluoride
from a catalyst mixture containing hydrogen fluoride when said catalyst
mixture is released into the atmosphere from a process system, said method
comprising admixing a sulfone with said catalyst mixture in an amount so
as to give a concentration of sulfone in said catalyst mixture in the
range of from about 2.5 weight percent to 50 weight percent and a weight
ratio of hydrogen fluoride to sulfone in said catalyst mixture of at least
1:1; and
releasing said catalyst mixture into the atmosphere from said process
system.
8. A method as recited in claim 7 wherein said concentration of sulfone in
said catalyst mixture is in the range of from about 5 weight percent to
about 30 weight percent.
9. A method as recited in claim 7 wherein said concentration of sulfone in
said catalyst mixture is in the range of from about 10 weight percent to
about 25 weight percent.
10. A method as recited in claim 7 wherein said sulfone is sulfolane.
11. A method as recited in claim 8 wherein said sulfone is sulfolane.
12. A method as recited in claim 9 wherein said sulfone is sulfolane.
Description
The present invention relates to a hydrocarbon conversion process and a
catalyst composition to be utilized in said hydrocarbon conversion
process. More particularly, the invention relates to an improved
alkylation process for the production of an alkylate product by contacting
hydrocarbon with a novel catalyst composition.
The use of catalytic alkylation processes to produce branched hydrocarbons
having properties that are suitable for use as gasoline blending
components is well known in the art. Generally, the alkylation of olefins
by saturated hydrocarbons, such as isoparaffins, is accomplished by
contacting the reactants with an acid catalyst to form a reaction mixture,
settling said mixture to separate the catalyst from the hydrocarbons, and
further separating the hydrocarbons, for example, by fractionation, to
recover the alkylation reaction product. Normally, the alkylation reaction
product is referred to as "alkylate", and it preferably contains
hydrocarbons having seven to nine carbon atoms. In order to have the
highest quality gasoline blending stock, it is preferred that the
hydrocarbons formed in the alkylation process be highly branched.
One of the more desirable alkylation catalysts is hydrofluoric acid,
however, the use of hydrofluoric acid as an alkylation catalyst has
certain drawbacks. One of the primary problems with the use of
hydrofluoric acid as an alkylation catalyst is that it is a highly
corrosive substance and it is toxic to human beings. The toxicity of
hydrofluoric acid to human beings is further complicated by the fact that
anhydrous hydrofluoric acid is typically a gas at normal atmospheric
conditions of one atmosphere of pressure and 70.degree. F. It is possible
for the vapor pressure of hydrofluoric acid at standard atmospheric
conditions to create certain safety concerns when it is exposed to the
atmosphere. These safety concerns are created by the ease with which
hydrofluoric acid is vaporized and released into the atmosphere.
In spite of the potential problems with human toxicity and the corrosive
characteristics of hydrofluoric acid, industry has in the past determined
that the benefits from the use of hydrofluoric acid as an alkylation
catalyst outweigh the potential problems. For instance, hydrofluoric acid
is an extremely effective alkylation catalyst in that it permits the
reaction of olefins by isoparaffins at low process pressures and process
temperatures. HF is particularly suited for use as a catalyst in the
alkylation of butylenes and, in the case of the alkylation of propylene
and amylenes, HF has been used as an effective catalyst whereas other
alkylation catalysts, such as sulfuric acid, have been found to be not as
effective in such alkylation services. Additionally, the alkylate formed
from a hydrofluoric acid alkylation process is of a very high quality
having such desirable properties as being a mixture of highly branched
hydrocarbon compounds that provide a high octane motor fuel. Generally, it
has been found that the alkylate produced by a hydrofluoric acid
alkylation process has a higher octane value than that produced by typical
sulfuric acid alkylation processes. Thus, it would be desirable to use an
alkylation catalyst that has the desirable features of hydrofluoric acid
catalyst but without having its high vapor pressure.
It is, therefore, an object of this invention to provide a novel alkylation
catalyst having the desirable property of yielding a high quality alkylate
when utilized in the alkylation of olefins with paraffins but having a
lower vapor pressure than that of hydrofluoric acid.
A further object of this invention is to provide a process for the
alkylation of olefins with paraffins in the presence of an alkylation
catalyst having the desirable property of having a reduced vapor pressure
but which produces a high quality alkylate product.
Thus, the process of the present invention relates to the alkylation of a
hydrocarbon mixture comprising olefins and paraffins with a catalyst
composition comprising the components of a hydrogen halide and a sulfone,
wherein the sulfone component is present in said catalyst composition in
an amount less than about 50 weight percent of the total weight of said
composition and wherein the weight ratio of hydrogen halide to sulfone is
at least 1:1.
The composition of the present invention comprises the components of a
hydrogen halide and a sulfone, wherein said sulfone component is present
in said composition in an amount less than about 50 weight percent of the
total weight of said composition and wherein the weight ratio of hydrogen
halide to sulfone is at least 1:1.
Other objects and advantages of the invention will be apparent from the
foregoing detailed description of the invention, the appended claims and
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graphical diagram illustrating at a given temperature the
change in vapor pressure of the novel hydrogen fluoride and sulfolane
catalyst mixture as a function of the weight percent sulfolane in the
catalyst mixture.
FIG. 2 is a graphical diagram comparing the selectivity of the process of
alkylating butylenes by isobutane when the novel hydrogen fluoride and
sulfolane catalyst mixture is utilized toward the production of
trimethylpentane as a function of weight percent sulfolane in the catalyst
mixture.
FIG. 3 is a graphical diagram comparing the ratio of trimethylpentane to
dimethylhexane contained in the product of the alkylation process that
uses the novel hydrogen fluoride and sulfolane catalyst mixture in the
alkylation of butylenes by isobutane as a function of the weight percent
sulfolane in the catalyst mixture.
FIG. 4 is a graphical diagram comparing the octane of the product of the
alkylation process that uses the novel hydrogen fluoride and sulfolane
catalyst mixture in the alkylation of butylenes by isobutane as a function
of the weight percent sulfolane in the catalyst mixture.
FIG. 5 is a graphical diagram comprising the calculated octane value of the
product of the alkylation process, in which a representative refinery feed
is processed, that uses the novel hydrogen fluoride and sulfolane catalyst
mixture as a function of the weight percent sulfolane in the catalyst
mixture.
FIG. 6 is a graphical diagram comparing the selectivity of the alkylation
process, in which a representative refinery feed is processed and the
novel hydrogen fluoride and sulfolane catalyst mixture is utilized, toward
the production of trimethylpentanes as a function of weight percent
sulfolane in the catalyst mixture.
The novel composition of the present invention is suitable for use as an
alkylation catalyst and can comprise, consist of, or consist essentially
of a hydrogen halide component and a sulfone component. The term
"consisting essentially of" as used herein when referring to the
alkylation catalyst composition is intended to mean that the composition
contains nothing, in addition to the requisite amount of hydrogen halide
component and sulfone component, which would have a substantial adverse
effect on the ability of the composition to act as a catalyst in an
alkylation reaction.
The hydrogen halide component of the catalyst composition or catalyst
mixture can be selected from the group of compounds consisting of hydrogen
fluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), and
mixtures of two or more thereof. The preferred hydrogen halide component,
however, is hydrogen fluoride, which can be utilized in the catalyst
composition in anhydrous form, but, generally, the hydrogen fluoride
component utilized can have a small amount of water. The amount of water
present in the hydrogen fluoride and sulfolane mixture in no event can be
more than about 30 weight percent of the total weight of the hydrogen
fluoride component, which includes the water, and preferably, the amount
of water present in the hydrogen fluoride component is less than about 10
weight percent. Most preferably, the amount of water present in the
hydrogen fluoride component is less than 5 weight percent. When referring
herein to the hydrogen halide component, or more specifically to the
hydrogen fluoride component, of the catalyst composition of the invention,
it should be understood that these terms mean either the hydrogen halide
component as an anhydrous mixture or a mixture that includes water. The
references herein to weight percent water contained in the hydrogen halide
component means the ratio of the weight of water to the sum weight of the
water and hydrogen halide multiplied by a factor of 100 to place the
weight ratio in terms of percent.
The sulfone component is an important and critical component of the
catalyst composition because of the several functions it serves and
because of the unexpected physical properties that it imparts to the
catalyst composition. One important function of the presence of the
sulfone component in the composition is its vapor pressure depressant
effect upon the overall catalyst composition. It is an essential aspect of
this invention for the sulfone component to be soluble in the hydrogen
halide component and for the sulfone component to be essentially
immiscible with olefin and paraffin hydrocarbons so as to permit easy
separation of the hydrocarbons from the catalyst composition. Also, it is
essential for the presence of the sulfone component to have a minimal
impact upon an alkylation reaction selectivity and activity.
Generally, those skilled in the art of hydrogen fluoride catalyzed olefin
alkylation processing have known that to obtain the highest quality of
alkylate from the aforementioned olefin alkylation process, it is
essential for the hydrogen fluoride catalyst to be as free from
contaminating compounds as is feasible. It is generally known that small
amounts of other compounds contained in the hydrogen fluoride catalyst of
an olefin alkylation process can have detrimental effects upon product
alkylate quality by negatively affecting the selectivity of the alkylation
reaction toward the production of more desirable end-product, such as, for
example, trimethylpentanes (TMP) in the case of the alkylation of
butylenes by isobutane. It is further known to those skilled in the art
that small amounts of components contained in a hydrogen fluoride
alkylation catalyst can have a negative impact upon its activity toward
the alkylation of olefins. Based upon the known effects of hydrogen
fluoride catalyst contaminants upon the activity and selectivity of the
alkylation process toward the production of high quality alkylate, one
skilled in the art would expect that the addition of small to large
amounts of a sulfone compound to a hydrogen fluoride catalyst would have
an enormously detrimental effect upon its catalytic performance. However,
it has been discovered that the presence of small quantities of a sulfone
compound in combination with hydrogen fluoride will have little negative
impact on the performance of the resultant mixture as an alkylation
catalyst, but, it is further unexpected that instead of having a
detrimental impact upon the catalytic performance, a small concentration
in an amount less than about 30 weight percent of a sulfone component in
combination with the hydrogen fluoride can enhance the performance of the
resultant composition as an alkylation process catalyst. Therefore, to
take advantage of the vapor pressure depressant effects of the sulfone
compound, it is desirable to utilize the sulfone in the catalyst mixture
in an amount in the range of from about 2.5 weight percent to about 50
weight percent. A concentration of the sulfone in the catalyst mixture
exceeding 50 weight percent has such a significantly negative impact upon
alkylate quality when the composition is utilized as an alkylation
reaction catalyst that the composition becomes ineffective as a catalyst.
Thus, 50 weight percent sulfone in the catalyst mixture becomes a critical
upper limit for the sulfone compound. In the situation where both vapor
pressure depression and improved catalytic activity and selectivity are
desired, the composition that works best in the alkylation of olefins has
less than 30 weight percent sulfone. To achieve optimal benefits from the
catalyst composition, the preferred catalyst mixture should contain the
sulfone component in the range of from about 5 weight percent to about 30
weight percent and, more preferably, the sulfone concentration shall range
from 10 to 25 weight percent.
In addition to the above-described concentration ranges and limitations for
the sulfone component of the catalyst mixture, it is essential, if not
critical, for the weight ratio of the hydrogen halide to sulfone in the
catalyst mixture to be at least about 1:1. The reason for such a minimum
weight ratio of hydrogen halide to sulfone in the catalyst mixture is that
the ratio of less than 1:1 has such a negative impact upon the alkylate
quality when the catalyst composition is utilized as an alkylation
reaction catalyst that composition becomes commercially ineffective as a
catalyst. Therefore, a 1:1 weight ratio of hydrogen halide to sulfone in
the catalyst mixture becomes a critical lower limit for this ratio.
The sulfones suitable for use in this invention are the sulfones of the
general formula
R--SO.sub.2 --R'
wherein R and R' are monovalent hydrocarbon alkyl or aryl substituents,
each containing from 1 to 8 carbon atoms. Examples of such substituents
include dimethylsulfone, di n-propylsulfone, diphenylsulfone,
ethylmethylsulfone and the alicyclic sulfones wherein the SO.sub.2 group
is bonded to a hydrocarbon ring. In such a case, R and R' are forming
together a branched or unbranched hydrocarbon divalent moiety preferably
containing from 3 to 12 carbon atoms. Among the latter,
tetramethylenesulfone or sulfolane, 3-methylsulfolane and
2,4-dimethylsulfolane are more particularly suitable since they offer the
advantage of being liquid at process operating conditions of concern
herein. These sulfones may also have substituents, particularly one or
more halogen atoms, such as for example, chloromethylethylsulfone. These
sulfones may advantageously be used in the form of mixtures.
This novel alkylation catalyst composition solves many of the problems that
herebefore have been encountered in typical alkylation processes that use
hydrofluoric acid as an alkylation catalyst. For instance, this novel
catalyst composition has a significantly lower vapor pressure than that of
the standard hydrofluoric acid alkylation catalyst. The advantage of using
an alkylation catalyst having a much lower vapor pressure than that of
hydrofluoric acid is that a lesser amount of the acid catalyst will
vaporize and enter into the atmosphere in cases where the catalyst is
exposed to the atmosphere. In particular, when making a comparison between
the novel catalyst composition and hydrofluoric acid, one notices a
significant difference in the vapor pressures of the two catalysts. The
effect of the presence of sulfolane mixed with hydrogen fluoride is
illustrated in the vapor pressure plot of FIG. 1. Since hydrofluoric acid
has a substantial vapor pressure at typical atmospheric or ambient
conditions, it is often in a vapor state at such conditions, and this
vapor pressure makes it a possibly less controllable compound in cases
where it is exposed to the environment.
The novel catalyst composition as described herein, solves many of the
problems associated with the use of hydrofluoric acid as a catalyst since
it provides the benefit of having a lower vapor pressure at ambient
conditions than that of hydrofluoric acid. But, in addition to the benefit
of having a lower vapor pressure at ambient conditions, the novel catalyst
composition further can be utilized in typical alkylation processes to
provide practical reaction rates at low operating pressures and low
operating temperatures to produce a high quality alkylate product which is
suitable for use as a blending component of gasoline motor fuel. A further
benefit from the novel catalyst composition is that it is easier to handle
commercially than hydrofluoric acid.
The benefits from the use of a hydrogen fluoride and sulfone catalyst
mixture is also illustrated in FIGS. 2, 3 and 4 in which is shown the
alkylate product quality that results from utilizing the novel hydrogen
fluoride and sulfone co-mixture to catalyze the reaction of mono-olefin
hydrocarbons by isoparaffins. As can be seen from FIG. 2, the total amount
of the more desirable alkylate product of trimethylpentane produced in the
alkylation reaction of butylenes with isobutane increases with increases
in the amount of sulfolane present in the alkylation catalyst mixture up
to an optimum range of about 10 weight percent sulfolane to about 25
weight percent sulfolane. Also, it is shown in FIG. 2 that there is a
maximum amount of sulfolane present in the catalyst mixture at which point
the alkylate quality becomes so undesirable that the hydrogen fluoride and
sulfolane mixture becomes ineffective as a catalyst. Based on the data
presented herein and in FIGS. 2, 3 and 4, it is believed that the critical
upper limit for the amount of sulfolane contained in the hydrofluoride and
sulfolane catalyst mixture is about 50 weight percent.
Alkylation processes contemplated in the present invention are those liquid
phase processes wherein mono-olefin hydrocarbons such as propylene,
butylenes, pentylenes, hexylenes, heptylenes, octylenes and the like are
alkylated by isoparaffin hydrocarbons such as isobutane, isopentane,
isohexane, isoheptane, isooctane and the like for production of high
octane alkylate hydrocarbons boiling in the gasoline range and which are
suitable for use in gasoline motor fuel. Preferably, isobutane is selected
as the isoparaffin reactant and the olefin reactant is selected from
propylene, butylenes, pentylenes and mixtures thereof for production of an
alkylate hydrocarbon product comprising a major portion of highly
branched, high octane value aliphatic hydrocarbons having at least seven
carbon atoms and less than ten carbon atoms.
In order to improve selectivity of the alkylation reaction toward the
production of the desirable highly branched aliphatic hydrocarbons having
seven or more carbon atoms, a substantial stoichiometric excess of
isoparaffin hydrocarbon is desirable in the reaction zone. Molar ratios of
isoparaffin hydrocarbon to olefin hydrocarbon of from about 2:1 to about
25:1 are contemplated in the present invention. Preferably, the molar
ratio of isoparaffin-to-olefin will range from about 5 to about 20; and,
most preferably, it shall range from 8 to 15. It is emphasized, however,
that the above recited ranges for the molar ratio of isoparaffin-to-olefin
are those which have been found to be commercially practical operating
ranges; but, generally, the greater the isoparaffin-to-olefin ratio in an
alkylation reaction, the better the resultant alkylate quality.
Isoparaffin and olefin reactant hydrocarbons normally employed in
commercial alkylation processes are derived from refinery process streams
and usually contain small amounts of impurities such as normal butane,
propane, ethane and the like. Such impurities are undesirable in large
concentrations as they dilute reactants in the reaction zone, thus
decreasing reactor capacity available for the desired reactants and
interfering with good contact of isoparaffin with olefin reactants.
Additionally, in continuous alkylation processes wherein excess
isoparaffin hydrocarbon is recovered from an alkylation reaction effluent
and recycled for contact with additional olefin hydrocarbon, such
nonreactive normal paraffin impurities tend to accumulate in the
alkylation system. Consequently, process charge streams and/or recycle
streams which contain substantial amounts of normal paraffin impurities
are usually fractionated to remove such impurities and maintain their
concentration at a low level, preferably less than about 5 volume percent,
in the alkylation process.
Alkylation reaction temperatures within the contemplation of the present
invention are in the range of from about 0.degree. F. to about 150.degree.
F. Lower temperatures favor alkylation reaction of isoparaffin with olefin
over competing olefin side reactions such as polymerization. However,
overall reaction rates decrease with decreasing temperatures. Temperatures
within the given range, and preferably in the range from about 30.degree.
F. to about 130.degree. F., provide good selectivity for alkylation of
isoparaffin with olefin at commercially attractive reaction rates. Most
preferably, however, the alkylation temperature should range from
50.degree. F. to 100.degree. F.
Reaction pressures contemplated in the present invention may range from
pressures sufficient to maintain reactants in the liquid phase to about
fifteen (15) atmospheres of pressure. Reactant hydrocarbons may be
normally gaseous at alkylation reaction temperatures, thus reaction
pressures in the range of from about 40 pounds gauge pressure per square
inch (psig) to about 160 psig are preferred. With all reactants in the
liquid phase, increased pressure has no significant effect upon the
alkylation reaction.
Contact times for hydrocarbon reactants in an alkylation reaction zone, in
the presence of the alkylation catalyst of the present invention generally
should be sufficient to provide for essentially complete conversion of
olefin reactant in the alkylation zone. Preferably, the contact time is in
the range from about 0.05 minute to about 60 minutes. In the alkylation
process of the present invention, employing isoparaffin-to-olefin molar
ratios in the range of about 2:1 to about 25:1, wherein the alkylation
reaction mixture comprises about 40-90 volume percent catalyst phase and
about 60-10 volume percent hydrocarbon phase, and wherein good contact of
olefin with isoparaffin is maintained in the reaction zone, essentially
complete conversion of olefin may be obtained at olefin space velocities
in the range of about 0.1 to about 200 volumes olefin per hour per volume
catalyst (v/v/hr.). Optimum space velocities will depend upon the type of
isoparaffin and olefin reactants utilized, the particular compositions of
alkylation catalyst, and the alkylation reaction conditions. Consequently,
the preferred contact times are sufficient for providing an olefin space
velocity in the range of about 0.1 to about 200 (v/v/hr.) and allowing
essentially complete conversion of olefin reactant in the alkylation zone.
The process may be carried out either as a batch or continuous type of
operation, although it is preferred for economic reasons to carry out the
process continuously. It has been generally established that in alkylation
processes, the more intimate the contact between the feedstock and the
catalyst the better the quality of alkylate product obtained. With this in
mind, the present process, when operated as a batch operation, is
characterized by the use of vigorous mechanical stirring or shaking of the
reactants and catalyst.
In continuous operations, in one embodiment, reactants may be maintained at
sufficient pressures and temperatures to maintain them substantially in
the liquid phase and then continuously forced through dispersion devices
into the reaction zone. The dispersion devices can be jets, nozzles,
porous thimbles and the like. The reactants are subsequently mixed with
the catalyst by conventional mixing means such as mechanical agitators or
turbulence of the flow system. After a sufficient time, the product can
then be continuously separated from the catalyst and withdrawn from the
reaction system while the partially spent catalyst is recycled to the
reactor. If desired, a portion of the catalyst can be continuously
regenerated or reactivated by any suitable treatment and returned to the
alkylation reactor.
The following examples demonstrate the advantages of the present invention.
These examples are by way of illustration only, and are not intended as
limitations upon the invention as set out in the appended claims.
EXAMPLE I
This example describes the experimental method used to determine the vapor
pressure of various hydrogen fluoride and sulfolane mixtures and to
present vapor pressure data for such mixtures demonstrating the
effectiveness of sulfolane as a vapor pressure depressant.
A 100 mL monel bomb was dried and evacuated, followed by the addition of a
prescribed amount of anhydrous hydrogen fluoride. A specific amount of
sulfolane was then added to the bomb. Once the bomb achieved the desired
temperature, the pressure within the bomb was recorded. The vapor pressure
was assumed to be that of HF vapor alone (sulfolane has a boiling point of
283.degree. C.). FIG. 1 presents a portion of the vapor pressure data
obtained by this experimental method and illustrates the change in vapor
pressure of the novel hydrogen fluoride and sulfolane catalyst mixture as
a function of the weight percent sulfolane in the catalyst mixture.
EXAMPLE II
This example describes the method which utilizes batch reactions to test
the feasibility of using a hydrogen fluoride and sulfolane mixture as a
catalyst for the alkylation of mono-olefins by isoparaffins. Data are
presented to demonstrate the unexpectedly improved properties of the
alkylate product from such a catalytic process and to demonstrate that for
certain concentration ranges the catalyst mixture unexpectedly provides a
good quality alkylate.
HF/sulfolane mixtures were evaluated for alkylation performance in batch
reactions at 90.degree. F. In a typical trial, the desired amount of
sulfolane was added to a 300 mL monel autoclave under a blanket of
nitrogen. Anhydrous HF was then introduced into the autoclave and heated
to 90.degree. F. with stirring at 500 RPM. The stirring was then increased
to 2500 RPM, and an 8.5:1 isobutane:2-butenes mixture was added with
nitrogen backpressure at a rate of 100 mL/min. at a pressure of 150-200
psig. After 5 minutes, the stirring was stopped, followed by the transfer
of the reactor contents to a Jerguson gauge for phase separation. The
hydrocarbon product was then characterized by gas chromatography.
The data presented in Table I were obtained by using the experimental
method described in this Example II. FIGS. 2 and 3 are graphical
representations of this data. FIG. 2 compares the selectivity of the
alkylation process toward the production of the highly desirable
trimethylpentanes as a function of weight percent sulfolane in the
catalyst mixture. FIG. 3 compares the ratio of trimethylpentanes to
dimethylhexanes contained in the alkylation product as a function of the
weight percent sulfolane in the catalyst mixture.
TABLE I
______________________________________
Batch Results, Anhydrous HF/Sulfolane
Test Samples
No. 1 No. 2 No. 3 No. 4
No. 5 No. 6
______________________________________
mL sulfolane
0.00 13.00 28.00 38.00
50.00 50.00
mL HF 100.00 93.50 86.00 81.00
75.00 50.00
mL Feed 100.00 93.50 86.00 81.00
75.00 100.00
wt. % sulfolane
0.00 15.09 29.39 37.49
46.02 56.11
% TMP 65.40 71.28 67.29 57.14
52.21 20.45
% DMH 9.63 9.02 10.52 11.90
12.28 1.58
TMP:DMH 6.79 7.90 6.40 4.80 4.25 12.97
C9+ 5.81 10.56 10.98 16.49
18.96 0.28
Organic fluorides
0.00 0.00 0.00 0.00 0.00 69.74
______________________________________
EXAMPLE III
This example describes the steady state evaluation method for testing the
feasibility of using a hydrogen fluoride and sulfolane mixture as a
catalyst for the alkylation of mono-olefins by isoparaffins. Data are
presented to demonstrate that for certain concentration ranges the
catalyst mixture unexpectedly provides a good quality alkylate.
A reactor was constructed to enable steady state evaluation of HF/sulfolane
alkylation catalysts using a 300 mL monel autoclave. A 10:1
isobutane:2-butenes feed was introduced into the autoclave with stirring
at 2000 RPM at a rate of 600 mL/hour. The reactor effluent flowed into a
monel Jerguson gauge for phase separation. The hydrocarbon phase was
passed through alumina and collected, while the acid phase was
recirculated to the reactor. Alkylate was evaluated by gas chromatography
and by research and motor octane tests performed on test engines.
The data presented in Table II were obtained by using the experimental
method described in this Example III. FIG. 4 is a graphical representation
of some of the data provided in Table II and compares the octane of the
alkylate product as a function of the weight percent sulfolane in the
catalyst mixture. As is evident from the data presented in Table II, the
alkylate quality degenerates at the point where the catalyst has a weight
ratio of hydrogen fluoride to sulfolane of less than 1:1. This
deterioration is demonstrated by that data presented which depicts
alkylate quality measures such as the concentration of C.sub.8 compounds,
the ratio of TMP to DMH, the concentration of C.sub.9 + compounds and the
octane of the alkylate. As is shown in Table II, the concentration of
C.sub.8 compounds and the ratio of TMP to DMH begin to significantly
decline when the alkylation catalyst has a ratio of hydrogen fluoride to
sulfolane of less than 1:1. Also, the concentration of undesirable C.sub.9
+ compounds in the alkylate begins to significantly increase when a
catalyst mixture having a ratio of hydrogen fluoride to sulfone is less
than 1:1.
TABLE II
______________________________________
70/30 HF/
60/40 HF/
50/50 HF/
40/60 HF/
100% HF sulfolane
sulfolane
sulfolane
sulfolane
______________________________________
C8 93.5 81.1 82.2 56.9 26.95
TMP 86.3 70.5 70.4 46.1 22.26
DMH 7.1 10.6 11.7 10.6 4.54
TMP/DMH 12.1 6.6 6.0 4.4 4.90
C9+ 3.4 3.9 8.1 23.1 36.32
R + M/2 97.0 95.5 94.9 93.7 NA
______________________________________
EXAMPLE IV
This example describes the steady state evaluation method for testing the
feasibility of using a hydrogen fluoride and sulfolane mixture as a
catalyst for the alkylation of a typical refinery feed mixture of
mono-olefins and isoparaffins (BB Feed). Data are presented to demonstrate
that for certain concentration ranges the catalyst mixture unexpectedly
provides a good quality alkylate.
A reactor was constructed to enable steady state evaluation of HF/sulfolane
alkylation catalysts using a 300 mL monel autoclave. The feed mixture of
olefins and paraffins presented in Table III was introduced into the
autoclave with stirring at 2000 RPM at a rate of 600 mL/hour. The reactor
effluent flowed into a monel Jerguson gauge for phase separation. The
hydrocarbon phase was passed through alumina and collected, while the acid
phase was recirculated to the reactor. Alkylate was evaluated by gas
chromatography and the octane values (R+M/2) were calculated using the
method for computing alkylate octane described in the publication authored
by T. Hutson, Jr. and R. S. Logan in Hydrocarbon Processing, September
1975, pages 107-110. This published article is incorporated herein by
reference.
TABLE III
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BB Feed
______________________________________
Hydrocarbons
Propylene 0.000
Propane 0.569
Isobutane 88.027
1-butene 2.818
Isobutylene 0.000
1,3-butadiene 0.000
n-butane 3.505
trans-2-butene 1.716
cis-2-butene 1.236
Isopentane 1.008
n-pentane 0.728
C.sub.5 olefins 0.393
100.000
Oxygenates
Acetone 29 ppm
Dimethyl ether 10 ppm
MTBE 1 ppm
______________________________________
The data presented in Table IV was obtained by using the experimental
method described in this Example IV. FIG. 5 is a graphical representation
of some of the data provided in Table IV and compares the calculated
octane value of the alkylate product as a function of the weight percent
sulfolane in the catalyst mixture. FIG. 6 compares the selectivity of the
alkylation process, in which a BB feed is processed, toward the production
of the highly desirable trimethylpentanes as a function of weight percent
sulfolane in the catalyst mixture.
TABLE IV
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98/2 80/20 HF/
65/35 HF/
60/40 HF/
100% HF HF/Water sulfolane
sulfolane
sulfolane
______________________________________
Hours 17 Hrs 13 Hrs 20 Hrs 7 Hrs 11 Hrs
C.sub.8 56.9 59.2 73.2 55.8 51.8
TMP 45.9 50.9 62.4 44.6 42.5
DMH 11.0 8.3 10.8 6.9 9.0
TMP/DMH 4.2 6.1 5.8 6.5 4.7
C.sub.9 +
3.9 2.6 4.2 11.4 6.8
(R + M)/2
92.5 94.2 95.7 92.1 91.7
(calculated)
______________________________________
While this invention has been described in terms of the presently preferred
embodiment, reasonable variations and modifications are possible by those
skilled in the art. Such variations and modifications are within the scope
of the described invention and the appended claims.
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